From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f200.google.com (mail-oi1-f200.google.com [209.85.167.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D5D0A41B8C5 for ; Mon, 20 Jul 2026 12:55:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784552146; cv=none; b=Oe5pmDMkM/gQtpE6QQCYpxyqiWYYh+2PmeygU8Vjc86VHo/bI4SF9mHGSPMhjPYUsCc4wsnANLVHEqYoLsVkV+racSxPPE/bLZa60h4I2SGw7G4Y9Q8i0ULVF99zRWLFdg0T/g1zBaFtQj3j2zOvNAHRhhVeX59EQFeuNMeYe9I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784552146; c=relaxed/simple; bh=bQubDadbhMw6JKdNcJpMLKSoHYd4j/P1EYF2sD4tY6w=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=l7uFAbnyP585hpeFpLiMS57XarT4643oYCSgPjShAJPYltaRTLRd+E07xASeJTO1IGfDF5o8xshAPUQ8vpWUhz3WJsGH0okc15HlGErZ0TXJMvhYFFdo9oqk1KE6007nZQho+c1N+rehMtTpBlZ5ga3B4pjhkG/AQ/Y5WjT19ac= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.167.200 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oi1-f200.google.com with SMTP id 5614622812f47-49d4cb3ca23so17607696b6e.3 for ; Mon, 20 Jul 2026 05:55:44 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784552144; x=1785156944; h=content-type:to:from:subject:message-id:in-reply-to:date :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to:content-type; bh=w4Ee8plrVMh/GBOkhRnZleDaiv4gwwDCTS9AHNO4rlc=; b=QJRT3AolnoZOuyjp5pFOS/OrW+aakKYW7ETseV/xq8AEUJmKez9RX2etTc4a+eGTmN GFjd/YYdnpm5M9U9ZcwNzEr+3HoRo7ix1oslEehUnNoL2JOYwwe3R76HEekqg6ev2KxA ZjaBDNbhydwb2Aq8CZ4RhnlYHGXsbrsEi+JbWjFlxo+W/eOhBq4TmtNoM1X+69ueQ5N9 XbMoVL/j0IbhdLloUyoHg7FrSThdLk4avb4XFCPLaM1IQYRiSkGU4bEzOUMdSgGRh14g BaTVvkgCf+RCRHTbNbjt47AQib55hNFEfFVfmgqUCwuVryx/jEDipddGNt8FCMGxcAGA 49Ug== X-Gm-Message-State: AOJu0YzuTxHdnUVehBx5OFJ+CJItCWioX5JXx31StRgcoEwmuFnMzEw9 tEYJW7O7DSM99G0+r7fzraxPnwfEb+m+fmwVATZOlwEDbjSDpsUTyuheNnzuiAMAkBh1p0nM1w0 cyicwYL5C5E05Y7CROhMFeGt0zc/Brqhd1pvXW4PD9VbagYbdYBI2cmZvM7Q= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:2207:b0:492:5bf0:d29e with SMTP id 5614622812f47-4a4d04f7e17mr7463129b6e.34.1784552143796; Mon, 20 Jul 2026 05:55:43 -0700 (PDT) Date: Mon, 20 Jul 2026 05:55:43 -0700 In-Reply-To: <6a426dd2.854d4ab9.360e1d.0008.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a5e1acf.5028b7d0.1f0bb.0327.GAE@google.com> Subject: Forwarded: Re: KASAN: use-after-free Read in kvm_setup_guest_pvclock From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: Re: KASAN: use-after-free Read in kvm_setup_guest_pvclock Author: halves@igalia.com #syz test Reported-by: syzbot+fb7c2dd166d3ea63df2a@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=fb7c2dd166d3ea63df2a Signed-off-by: Heitor Alves de Siqueira --- virt/kvm/pfncache.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/virt/kvm/pfncache.c b/virt/kvm/pfncache.c index 728d2c1b488a..8a766c4cd4bd 100644 --- a/virt/kvm/pfncache.c +++ b/virt/kvm/pfncache.c @@ -152,6 +152,32 @@ static inline bool mmu_notifier_retry_cache(struct kvm *kvm, unsigned long mmu_s return kvm->mmu_invalidate_seq != mmu_seq; } +static void kvm_gpc_invalidate_pfn(struct kvm *kvm, kvm_pfn_t pfn) +{ + struct gfn_to_pfn_cache *gpc; + + if (is_error_noslot_pfn(pfn)) + return; + + spin_lock(&kvm->gpc_lock); + list_for_each_entry(gpc, &kvm->gpc_list, list) { + read_lock_irq(&gpc->lock); + + if (gpc->valid && gpc->pfn == pfn) { + read_unlock_irq(&gpc->lock); + + write_lock_irq(&gpc->lock); + if (gpc->valid && gpc->pfn == pfn) + gpc->valid = false; + write_unlock_irq(&gpc->lock); + continue; + } + + read_unlock_irq(&gpc->lock); + } + spin_unlock(&kvm->gpc_lock); +} + static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cache *gpc) { /* Note, the new page offset may be different than the old! */ @@ -201,6 +227,7 @@ static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cache *gpc) if (new_khva != old_khva) gpc_unmap(new_pfn, new_khva); + kvm_gpc_invalidate_pfn(gpc->kvm, new_pfn); kvm_release_page_unused(page); cond_resched(); @@ -221,6 +248,7 @@ static kvm_pfn_t hva_to_pfn_retry(struct gfn_to_pfn_cache *gpc) new_khva = gpc_map(new_pfn); if (!new_khva) { + kvm_gpc_invalidate_pfn(gpc->kvm, new_pfn); kvm_release_page_unused(page); goto out_error; } -- 2.55.0